Refrigerating apparatus



Nov. Z5, 1930.Y J. F. HOFFMAN 1,782,689

I REFRIGERATING APPARATUSv Filrd April 16, 19278 2 sums-sheet 2 Illlllllll// /Illllllll//l Ill/llllll/1111111111111111111111Ill/1 l l 'lili/lllIlIllllIlll/llIlllIlllllllllIll/l lll/111111111111,

lill/111111 PlIlIlIllllllllllllI/l/Illl/llIl/l/ Patented Nov. 25, 1930 UNITED STATES PATENT oFEicE TOI-IN F. HOFFMAN, OF OMAHA, NEBRASKA, ASSIGNOR TO BAKER ICE MACHINE CO. INC.,

OF OMAHA, NEBRASKA, A CORPORATION F NEBRASKA REFRIGERATING APPARATUS I Application lel April 16,

My invention relates to refrigerating systems and more particularly to systems having a plurality of compartments provided with coils supplied with refrigerant from a common source and having intercommunicating return lines, the principal object of the invention being to control such a system automatically for producing and maintaining differential temperatures in the several compartments.

Further objects are to prevent the exchange of heat between units through the return line, to retain th-e refrigerant in a unit when the supply thereto is suspended, to suspend the supply to al unit by means responsive to the temperature. thereof, to open an outlet from a unit when the inlet thereto is opened,fand to prevent the flow of refrigerant through a unit when return line conditions might interfere with refrigeration by said unit.

The present application pertains to certain variations in structure and mode of operation of refrigerating apparatus disclosed in my co-pending application, Serial No. 209,691. A

In accomplishing the above named an other objects of the invention I have provided improved details of structure, the preferred 'forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a diagrammatic view of a refrigerating system embodying my invention and illustrated as including three compartments, 1 brine tank, a source of refrigerant supply, and controlling means.

Fig. 2 is a vertical sectional view, partly diagrammatic, of the means provided for.

each unit for controlling the flow of refrigerant therethrough, valves being illustrated in flow-suspending position, and a pressureactuated relay belng illustrated as preventing the actuation of a thermostatically opereated switch to permit opening of an inlet valve.

Referring in detail to the drawings:

1 designates a compressor, 2 a condenser, 3 a receiver, 4 a supply line, and 5, 6 and 7 individual compartments designed for di'f- Eerential cooling by Huid delivered from the 1928. Serial N0. 270,252.

condenser through the supply line to coils, such as 8, positioned in the compartments. A brine tank 9 is included in the system and is also provided with one of the coils 8. The fluid passes from the coils through a suction or return line 10 back to the condenser, the connections between the supply line, returnline and coils including elements which will be particularly described. The equipment in the several compartments, and tank, is substantially identical and one assembly or unit will be described.

A branch line 11 controlled by spaced man. ual valves 12 and '13 leads from the supply line 4 toward the coil 8 in the compartment 5. Interposed between the valves 12 and 13 is a heat-actuated and thermostatically controlled supply control valve 14, a pressure` actuated outlet control fitting 15 and a pressure-actuated volume control valve 16 whereby the supply and the outflow of fluid to and from the compartment are automatically set up, regulated and suspended, as presently described.

A by-passing'branch 17 provided with a valve 18 is connected into the supply branch at 17a and 17 b between the manual valves 12 and 13, and outside of said valves 14 and 16 and fitting 15, for delivering the refrigerant in a major flow to the coil, the incidental fluctuations in load under succeeding operations being regulated by functioning of said members 14, 15 and 16.

In systems of this character it is desirable that fluid be required to perform useful work before passing out of the coils and I provide the valve mechanism generally designated 16 for automatically controlling supply of refrigerant to the coils in proper volume and as required for maintaining the compartment served by the coil at a desired temperature.

The valve 16 comprises a body member 19 having a receiving chamber 20 adjacent its inlet end containing a screened scale trap 21 that rests on a clean-out plug 22. A tube 23 leads from the chamber 2O ,through a valve fitting 24 containing a manually operable valve represented by the handle 25, into a boreI 26 in avalve cap member 27 suitably 100 secured to the body 19. The tube 23 communicates through the bore 26 and a conduit 28 with a condenser jacket 29 through which an outlet pipe 30 from the coil extends, so that fiuid may be delivered from the supply line to the condenser jacket through said tube, fitting, bore and conduit. A bore 31 leads from the receiving chamber 20 of the valve to a lower chamber 32 in the body member and this chamber communicates through an opening 33 with an upper chamber 34 from which a bore 35 leads toward the lower convolution of the coil, for passage of fluid through the valve to the coil.

A nipple 36 positioned in said opening 33 is provided at its lower end with a retaining flange 37 providing a ball seat 38 to receive a ball valve 39, the ball valve being normally held against said seat by a spring 40 bearing against a lower plug member 41 attached to the body member, and being adapted to control flow of fluid through the valve. The ball is movable from its seat by a pin 42 located in the nipple but permitting flow of fluid therethrough, the upper end of the pin being engaged by a plate 43 having a depending sleeve 44 slidable over the nipple and provided with side ports 45 through which fluid may pass from the nipple to the chamber 34. The plate 43 is fixed on the lower face of a diaphragm 46 having edges held between the -valve body 19 and cap member 27, the diaphragm being influenced by pressure of the fluid in achamber 47 of the cap member that communicates through the bore 26 and conduit 28 with the condenser jacket. A coil spring 48 seated in a cup 49 that bears on the diaphragm 46 is set at a desired tension by a flanged set screw 50 engaged in a suitable opening in the cap, a lock nut 51 fixing the set screw in springadjusting position; When fluid is passing -at too low a temperature from the coil into the return line, cooling thereby of the fiuid in the condenser jacket and consequent reduction in pressure thereof relieves Huid pressure on the diaphragm and permits upward movement of the ball valve under the infiuence of the spring 40 to restrict the flow through the valve to the coil. Higher temperature in said condenser jacket, resulting from the efiicient withdrawal of heat fromthe compartmentby the refrigerant causes expansion of the fluid in the condenser jacket and pressure thereof through the chamber 47 to alter the position of the ball valve and permit freer flow of refrigerant through the supply branch into the coil. The above described regulating device is designed for automatic modification of the supply of refrigerant to the coil by various conditions of thel refrigerant after it leaves the coil.

In order to automatically suspend the delivery of refrigerant to a unit when the temperature of the compartment has reached the desired low degree, I constitute the valve member 14 an electro-thermically controlled pressure valve comprising a body member 52 having an annular recess 53 in its upper face producing` a central boss 54` and an inlet port 55 communicating with the recess 53, and a cap member 56. A diaphragm 57 having its periphery retained between the cap and the body member is seatable on said boss to close an outlet port 58 extending through the boss, the diaphragm closing a recess 59 in the lower face of the cap member to constitute said recess an expansion chamber. The diaphragm is held in a desired relation with the boss by a spring 60 which permits the normal pressure of the supply fluid to displace the diaphragm for passage of fluid from the inlet port and annular recess thrlough the outlet 58 onwardly toward the co1 A casing 61 is fixed to the cap'member 56 and a heat-conducting tube 62 is positioned in the casing in communication with the eX- pansion chamber 59, the tube and chamber being supplied with a fluid pressure agent through a bore 63 closed by a needle valve 64; the supply preferably being provided from the flow line through a bore 65 in the body 52 and an opening 66 in the diaphragm registering with said bore. A bulb 67 positioned in the casing is ada ted to heat the fiuid contained in the coil or expansion in the chamber 59 to urge the diaphragm toward the outlet port 58 against the pressure of the incoming supply fiuid. The bulb is supplied with current through a circuit including wires 68 and 69, and is energized according to temperature conditions in the compartment. i A thermostatic device 70 contained with- 1n the casing 61 comprises a mercury tube 71 tiltingly supported by a link 72 attached to the side of the casing, and contact points 73 and 74 fixed in the tube and interposed in the line 69, the points being adapted to close the circuit when bridged by mercury 75 movable in the tilting tube. The heat generated by the bulb tends to change' the shapev'of t-he link and cause the tube to tilt to move the mercury into or out of contact-bridging position. The circuit is manually controlled by a switch 76.

Closing of the manual switch conditions the circuit for automatically actuating the diaphragm to close the supply valve 14; and the circuit, after being broken upon attainment of a predetermined degree of heat in the casing, will be re-established automatically upon cooling of the casing and return of thelink 72 to normal condition. The mercury switch, therefore, serves to prevent excessive and undesirable temperature in the casing, and excessive pressure on the diaphragm, which might cause deterioration of parts.

The energization of the bulb for control of the'supp'ly valve 14 is further regulated, however, by interposition of a second element in the circuit, namely, a thermostatically controlledA switch 77 preferably positioned within the compartment and comprising a sylphon bellows 78 having an elbo'w link 79 pivotally connected to one end of a centrally fulcrumed lever 80, the opposite arm of the lever being pivotally connected with a link 81 thatris connected to the lower end of a pivoted clasp 82 xed to and supporting a mercury tube 83, the upper end of the clasp being pivotally mounted on. a pin 84. Relatively high temperature in the com-l partment causes expansion of the bellows,

rocking of the lever, depression of the link 81, and tilting of the mercury tube to causel mercury 85 therein to. flow away from bridgeing relation with contacts 86 and 87 fixed in the tube and Ainterposed in the circuit line 69. The breaking of the circuit suspends the energization of the bulb 67 in the casing 61 of the valve member 14, thereby permitting cooling of the fluid in the expansion chamber 59, relieving pressure on the diaphragm 57, and permitting flow of refrigerant through the supply line valve 14 into the coil of the compartment, subject to the influence of the spring 60.

Cooling of the compartment to the desired degree by evaporation of the refrigerant passing therethrough will cause contraction of the bellows 78, opposite tilting of the mercury tube, and closing of the circuit through the terminalsl 86 and 87 to energize the bulb 67 and cause the diaphragm 57 to seat on the boss 54, `close the outlet 58 and suspend fiow through the supply branch to the compartment. The supply of refrigerant is thus automatically Set up or shut 0H by the thermostat that is subject to the temperature of the compartment.

When tlie compartment has been cooled to a desired degree, it is necessary not only to cut off the supply of refrigerant from the coil but to retaimthe refrigerant in the coil and I provide means for preventing outflow from the coil subject to the inflow of the refrigerant to the coil and including an outlet valve88 in the outlet pipe 30 exterior to the condenser jacket. The valve 88 comprises a body member 89 having an inlet port 90 communicating with a central through bore 91, an'outlet channel 92 connected with the vreturn line, a cap 93 fixedto the body by bolts ,94, and a plate valve 95 normally retained on a seat 96 by la spring 97 to close the bore and, obstruct flow through the valve.

The spring 97 bears against a fianged set v screw 98engaged in a threaded opening 99 in the calp'93,lwhich is retained in set Vposition byia lock nut 100fr suitably tensioning the= spring to resist pressure of the refrigerant departing from the coil and permit flow into the return line under predetermined condition of the departing refrigerant.

To assure openingof the plate valve 95.

chamber 102 formed by a recessed cap mmber 103 fixed to the valve body member 89 and a diaphragm 104 having its periphery engaged between the body member 89 and the cap member 103, and a pin105 projecting from the plate valve 95 through the bore 91 fixed in a follower disk 106 attached to the diaphragm, whereby movement of the diaphragm will cause reciprocation of the pin and movement of the plate valve with reference to the seat 96. Predetermined pressure of the fiuid in the tube 101 bearing against the diaphragm Awill cause the valve to move away from the seat, and absence of such pressure, due to suspension of supply flow through the valve 14, will permit the spring 97 to retain the valve in outlet-closing position.

The delivery of refrigerant to the coil, and flow of refrigerant from the coil, are thus automatically controlled and regulated by temperature conditions peculiar to the coil and the compartment, and the apparatus, including the several similar units, will operate automatically to establish and maintain the differential temperatures in the several compartments and the tank. Provision is further made to suspend actuation of the compressor when the inlets and outlets of all thev coils are closed, comprising a switch 107 actuated by pressure conditions in the return line for opening and closing a circuit 108 lto the compressor motor'. p

When temperature conditions in a compartment cause opening of the outlet and inlet valves, the pressure built up in thereturn vline will cause the actuation of the switch 107 for closing the circuit to start the compressor motor, and when the pressure in the return to open` the compressor motor circuit, the details' of such motor control being described more fully in my copending application above referred to.

The automatic closing of a coil outlet Vvalve 88 upon suflicient cooling of the compartment lserved by the coil prevents effect on the refrigerantin such compartment by refrigerwhile conditions in the return line would af' fect the refrigerant in the coil. I, therefore, provide means for preventing the actuation of the switch 77 except when the return line conditions are favorable for opening the valve 88, including a relay control generally designated 109 whereby predetermined pressure in the return line may restrain the thermostatic supply-inlet control 77 from break ing the circuit to the bulb 67.

The relay control 109 comprises a conduit 110 having one end connected intothe return line at 111 adjacent the valve 88 and an opposite end connected into a pressure relay housing 112 having a bearing opening 113 in which a pusher rod 114 is slidably mounted, the inner end of the rod being fixed to a diaphragm 115 extending across the houslng and dividing the same into fluid-receiving 1 and spring-containing chambers 116 and 117 respectively. The diaphragm is movable by pressure o f fluid conducted through the conduit into the chamber 1 16 to urge the rod against the link 81 and prevent the actuation of the mercury switch to open the circuit 68-69, de-energize the bulb 67 and permit supply line fluid pressure to open the inlet' valve 14. The rod is normally restrained in spaced relation with the link by a spring 118.

en pressure in the return line is lowered, the pusher rod is retracted by the spring 118 to permit the thermostatic control 77 to operate.

It is to be'understood that each of the three compartments, and the brine tank, is`

provided with inlet and outlet connections including the several control elements, and that a single compressor-motor control switch is provided in the suction line. Suitable pressure gauges are provided in the several lines, such as the gauge 119'in the return line and the gauges 120 in the conduits '28. A manual valve 121 controls the supply line 4.

A system and apparatus having been installed as above described, its conditioning for operation, and its operation, are as folows:

It will be aumed that the temperatures to be established and maintained in the several compartments and brine tank are respectively: compartment 5, 10; compartment 6, 20; compartment 7, 30; brine tank 9, 0. The thermostats 77 are adjusted for response to the indicated temperatures. The switch 76 is opened to break the circuit through the thermostats.

in the usual manner, and the system is charged with refrigerant such as ammonia. The supply valve 121 is then closed, and the usual manual electric switch is set to actuate the compressor motor for pumping the refrigerant into the receiver.

When the pressure gauge in the suction line indicates a vacuum, the small charging valves 64 and 25 in the valves 14 and 16 are closed, the manually operated supply branch valves 13 are closed, and the supply line valve 121 is opened to permit flow of refrigerant through the supply branches and valves 14, fitting 15 A and conduits 101, and valves 16 toward the coils, the incoming refrigerant being stopped by the valves 13 at the inlet ends of the coils. The valves 25 and 64 are then opened sufficiently to admit fluid into the chambers 47 and 59, and to the conduit 28 for filling the condenser jackets 29, the valves 25 and 64 being closed when the pressure gauges 120 show suitable pressure, for example, 100 pounds. The fluid is thus retained and sealed in the chambers and connected passages, to serve as an expansible agent forcontrolling the valves 16 and 14 respectively.

The valves 13 for the several coils are then opened to permit the refrigerant to pass into the coils where the expanding refrigerant imparts its energy to the compartment and receives heat therefrom.

It is to be noted that the thermostats 77 are conditioned by the relatively high temperatures of the compartments to open the circuits to the bulbs controlling the inlet valves 14. Flow of refrigerant toward the coils from the inlet valves 14 results in passage of fluid under supply line pressure conditions, for example, 180 pounds, through the conduits 101 into the valves 88 to move the plate valves from their seats and permit the refrigerant to pass into the return line after withdrawing heat from the compartments.

While the refrigerant is thus permitted to flow from the coils, taking up heat from the compartments, its temperature conditions influence the fluid in the condenser jackets to regulate the openings in the valves 16 for increasing or decreasing the supply of refrigerant to the coils, and for completely closing or opening these valves.

en am7 one compartment has been cooled to the temperature predetermined therefor, the thermostat 77 therein will be operated. namely, by contraction of the sylphon bellows, and will operate the mercury switch to close the circuit to the bulb associated with the inlet valve 14 of the coil of this compartment, whereupon the fluid agent in the chamber 59 is expanded to urge the diaphragm against the boss of the valve and close the supply port. Suspension of supply branch between the valve 14 and the coil to that Opressure which is present in the coil, forexample, 25 pounds, and thus the pressure in the conduit 101 is reduced below the effective degree, whereupon the spring in thevalve 88 is permitted' to move the plate valve tqrits seat and thereby close the outlet The refrigerant-being retained in the coils ceases to lwithdraw heat therefrom and the compartments will maintain their predetermined and differential temperatures over a consid erablc period. l

It is apparent that the coils in thecompartments requiring higher temperature will first be closed.- VVhen'all the coils are closed, the reduction `of pressure in the return line results in actuation of the switch to st'op the The outlet valves when closed prevent equalization of heat between the differentially cooled compartments, 'through the common return line. i

Should any compartment require resump- 1 tion of refrigerating service, the thermostat 77 therein will be actuated byrising temperature to open the circuit to the bulb in the valve 14, whereupon cooling of the fluid in the chamber 59 will permit the supply pressure to open the valve and the fluid will flow therethrough into the coils. The pressure of the incoming fluid exerted through the conduit 101 against the diaphragm in the valve 88 will open the plate valve and permit outflow of the refrigerant from the coil synchronously with the inlet of the supply. The rise in pressure in the return line due to flow vof fluid from the opened coil causes actuation of the compressor-motor switch to start the motor.

The presence of fluid passing through the suction line,delivere d thereto from a coil opverating on a compartment requiring relatively high temperature, for example, compartment 7, might interfere with the 'efficient service of the coil serving compartment 5, which requires resumption of refrigerating influence to maintain a temperature of 10. The pressure of such iiuidin the return line is exerted through the relay conduit leading to the relay control housing associated with `the supply branch to compartment 5, and urges the rod in said housing into contact with the link of the thermostat 77, thereby preventing the sylphon bellows from actuating the mercury switch, and thus preventing the opening of the inlet and outlet valves connected with the i coil in compartment 5.

When the suction line conditions are suitcircuit to permit the inlet valve 14 to ope'n and the supply branch pressure to open the outlet valve 88.

Itis, therefore, apparent that I have pro-- vided automatic means for controlling the circulation.ofrefrigerant through a plurality of coils having common supply and return lines and adapted for differentially cooling a plurality of compartments whereby the handicaps to most efficient control of such a system by manual means are overcome, anydemand ofa compartment for suspension or resumption of refrigeration is instantly met, conditions in one compartment and in the suction line are prevented from interfering with or modifying the conditions in any other compartment, and a high degree of accuracy is effected in the operation of the system.

The commodities located in the compartments, and the brine in the tank, arev therefore cooled to the proper and predetermined degrees and maintained at such degrees for their proper preservation.

What'I claim and desire to secure by Letters Patent is:

1. In a refrigerating system including a plurality of coils, a supply line, and a return line, an inlet valve and an outletvalve serving each coil, and means operable by pressure in the supply end of the coilcontrolllng the outlet valve. ,Y

2. In a refrigerating system including a plurality of coils, a supply line and a return line; an inlet valve to each coil operable by the pressure in the supply line, an outlet valve valve operable by supply line pressure upon opening of the corresponding'inlet valve, and

means for closing each inlet valve against the pressure in the supply line. y

3. In a refrigerating system including, a plurality of coils, a supply line and a return line, an inlet valve and an outlet valve serving each coil, and means operable by pressure in the supply line admitted through the inlet valve for actuating the outlet valve. A

4; In combination with a coil serving a compartment and supply and return lines connected with the coil, a normally closed valve inthe supply line opened by pressurev inthe supply line, and means for effecting closure of the valve Vagainst said pressure including means responsive to lowering temperature in said compartment.

5. In a compartment-cooling apparatus, in combination with a coil, and supply and return lines connected with the coil;a valve in the supply line, a plurality of independent means forclosing the valve, and means responsive to temperature inthe compartment controlling one of said valve closing means.

6. In combination with a coil, and supply and return lines connected with the coil, a normally closed valve in the supply line responsive to pressure of fluid flowing through said supply line, temperature-responsive means for closing the valve, and means responsive to increasing temperature in a compartment served by the coil for actuating said valve-closing means.

7. In combination with a coil positioned in a compartment for cooling the same, and supply and return lines connected with the coil, a normally closed valve in the supply line adapted for opening by pressure in the supply line, a normally closed valve in the return line, means for opening the return line valve responsive to pressure from the supply line when the supply line valve is open, and means for closing the supply line valve against the pressure in the supply line responsive to increasing temperature in the compartment.

8. A refrigerating system including a plurality of independent coils, a supply line and a return line, branches connecting said lines with each coil, a valve in each supply brantli normally opening under pressure in the supply line, a normally closed valve in each return branch, a conduit leading from each supply branch to the corresponding returnbranch valve, means movable by pressure of.`

fluid admitted through said supply branch valve to the conduit for opening said return branch valve, and temperature-responsive means for closing said supply branch valve.

9. In a refrigerating plurality of coils havin common supply and return lines, a norma yclosed inlet valve and a normally closed outlet valve serving each coil, the inlet valve vnormally opening under pressure of the Huid in the supp y line, means including a bulb and an electric circuit for closing the inlet valve, means responsive to temperature for closing said inlet valve-closing circuit, and means operable upon the opening of the inlet valve for opening the outlet valve.

10. In a refrigerating system comprising a plurality of compartments, a plurality of coils having common supply and return lines, each coil serving one of the compartments, an inlet valve and a normally closed outlet valve serving each coil, the inlet valve being normally closed and adapted for opening by pressure in the supply line, means including a thermostat responsiveto temperature conditions of the compartment for closing theinlet valve against the pressure in the supply line, means operable upon the opening o the inlet valve for opening the outlet valve, and means responsive to pressure in the return line for engaging said thermostat to retain the same in inlet-valve closing posit-ion.

11. In a refrigerating apparatus, a plurality of compartments, a supply line, a resystem including a t-urn line, a plurality of coils serving the compartments, branches ofthe supply and return lines connected respectively with the coils, means controlling the ilow through said branches to and from each coil including a thermostat positioned in each compartment and having an operable link, and means responsive to pressure in the return line for preventing operation of t e thermostat under increasing temperature o the compartment served thereby includin a tube connected with the return line, a ousing, and a rod supported by the housing and movable by pressure of fluid in the return line into engagement with said link to retain the thermostat in nonactuating position against the influence of increasing temperature in said compartment.

In testimony whereof I 'aliix my signature.

` JOHN -F. HOFFMAN. 

